1. Field of the Invention
The present invention relates to a book binding apparatus for perfect book binding. The book binding apparatus for perfect book binding comprises a conveying path, a series of processing units carrying out perfect book bind processing, a clamp unit provided with a pair of clamping plates and arranged for reciprocal movement along the conveying path, and a clamp unit driving mechanism reciprocating the clamp unit. The perfect-binding book binding processing is carried out while a book block is clamped between the pair of clamping plates and passes through the series of processing units in succession.
2. Description of the Related Art
There is known a conventional book binding apparatus continuously receiving book blocks of one book from a printer and a copying machine, and carrying out perfect book bind processing of book blocks one by one.
FIG. 4 is a schematic perspective view of a structure of one example of such a conventional book binding apparatus. Referring to FIG. 4, the conventional book binding apparatus for perfect book binding comprises a conveying path F, a series of processing units (milling unit B, glue application unit C and cover application unit D) which are arranged along the conveying path F for carrying out the perfect book bind processing, a clamp unit provided with a pair of clamping plates 1a and 1b and arranged for reciprocal movement along the conveying path F (only clamping plates 1a and 1b are shown in FIG. 4), and a clamp unit driving mechanism (not shown) reciprocating the clamp unit.
A book block P is subjected to the perfect-binding book binding processing while the book block P passes through the series of processing units in succession after the book block P is nipped by the pair of clamping plates 1a and 1b which is on standby at a book block inserting position A.
The pair of clamping plates 1a and 1b is composed of a stationary clamping plate 1a and a movable clamping plate 1b. The clamp unit comprises gap adjustment means (not shown) moving the movable clamping plate 1b in directions toward and away from the stationary clamping plate 1a. Before the book binding processing is started, the clamp unit is on standby in the book block inserting position A, and a gap between the pair of clamping plates 1a and 1b is previously adjusted according to the thickness of the book block P. When the book binding processing is started, in the book block inserting position A, the book block P is placed on an aligning plate 1c arranged in the book block inserting position A in such a manner that a back surface of the book block P faces downward, the book block P is inserted between the pair of clamping plates 1a and 1b of the clamp unit, and the book block P is nipped therebetween. Thereafter, the book block P is conveyed to the milling unit B by the clamp unit along the conveying path F.
The milling unit B comprises a milling cutter 2a and a pair of guide plates 2b and 2c. The pair of guide plates 2b and 2c is composed of a stationary guide plate 2b and a movable guide plate 2c. The movable guide plate 2c is moved by the gap adjustment means (not shown) in directions toward and away from the stationary guide plate 2b. A gap between the pair of guide plates 2b and 2c may be adjusted. Before the book binding processing is started, the pair of guide plates 2b and 2c is in a standby state where the gap therebetween is previously adjusted according to the thickness of the book block P. While the book block P nipped between the pair of clamping plates 1a and 1b passes above the milling cutter 2a, both sides of a back surface portion of the book block P protruding from the pair of clamping plates 1a and 1b are inserted between the pair of guide plates 2b and 2c. The both sides of the back surface portion of the book block P are thereby supported by the pair of guide plates 2b and 2c and the back surface of the book block P is grinded, and preprocessing for uniform application of glue on the entire back surface of the book block P is carried out. Then, the book block P nipped between the pair of clamping plates 1a and 1b is conveyed to the glue application unit C.
The glue application unit C comprises a glue tank 3a filled with glue, a gluing roller 3b, and a roller 3c for wiping excessive glue off. The glue application unit C applies an appropriate thickness of glue on the back surface of the book block P. When the gluing operation is completed, the book block P nipped between the pair of clamping plates 1a and 1b is conveyed to the cover application unit D.
The cover application unit D comprises a bottom plate 4c and a pair of nip plates 4a and 4b. The pair of nip plates 4a and 4b is composed of a stationary nip plate 4b and a movable nip plate 4a. A gap between the pair of nip plates 4a and 4b can be adjusted by moving the movable nip plate 4a by the gap adjustment means (not shown) in directions toward and away from the stationary nip plate 4b. Before the book binding processing is started, the pair of nip plates 4a and 4b is in a standby state where the gap therebetween is previously adjusted according to the thickness of the book block P. When the book binding processing is started, a printed cover Q is supplied onto the bottom plate 4c and the pair of nip plates 4a and 4b in a direction of an arrow S by appropriate conveying means such as a conveyer from a cover collecting section (not shown). Thereafter, the book block P nipped between the pair of clamping plates 1a and 1b stops at a position where the back surface of the book block P is opposed to a spine of the cover Q. Then, the bottom plate 4c and the pair of nip plates 4a and 4b rise, the cover Q is pressed against the spine of the book block P by the rising bottom plate 4c and at the same time, the movable nip plate 4a is moved toward the stationary nip plate 4b, and thereby the cover Q is pressed against both sides of the back surface of the book block P, the cover Q is glued on the book block P and a bound matter is completed. Thereafter, the clamp unit returns to the book block inserting position A, where the pair of clamping plates 1a and 1b is fully opened, the bound matter is discharged.
In the book binding apparatus for perfect book binding, it is often necessary to change the thickness of the book block P to be bound. In such a case, the gap between the pair of clamping plates 1a and 1b of the clamp unit on standby, the gap between the pair of guide plates 2b and 2c on standby of the milling unit B, and the gap between the pair of nip plates 4a and 4b on standby of the cover application unit D need to be adjusted.
Therefore, the conventional book binding apparatus for perfect book binding comprises a measuring unit for measurement of the thickness of the book block P so that the gap between the pair of clamping plates 1a and 1b on standby, the gap between the pair of guide plates 2b and 2c on standby of the milling unit B, and the gap between the pair of nip plates 4a and 4b on standby of the cover application unit D can be adjusted at once based on the measured value.
According to this structure, however, it is not possible to carry out the measuring operation of the thickness of the book block P, and the adjusting operation of the gap between the pair of guide plates 2b and 2c on standby and the gap between the pair of nip plates 4a and 4b on standby until the pair of clamping plates 1a and 1b returns to the book block inserting position A. When the thickness of the book block P is frequently changed, there is a problem that a rate of operation of the book binding apparatus for perfect book binding is significantly deteriorated.